package com.kingbook.common.utils;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

import java.util.Map;

@Component
@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)
public class SpringContextUtils implements ApplicationContextAware {

	  private static ApplicationContext applicationContext;

	  /**
	  * 实现ApplicationContextAware接口的回调方法，设置上下文环境
	  * @param applicationContext
	  * @throws BeansException
	  */
	  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
	    SpringContextUtils.applicationContext = applicationContext;
	  }

	  /**
	  * @return ApplicationContext
	  */
	  public static ApplicationContext getApplicationContext() {
	    return applicationContext;
	  }

	  /**
	  * 获取对象
	  * @param beanName
	  * @return Object 一个以所给名字注册的bean的实例
	  * @throws BeansException
	  */
	  public static void registerBean(String beanName, Object obj) throws BeansException {
		  DefaultListableBeanFactory acf = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
		  acf.registerSingleton(beanName, obj);
	  }


	  public static void removeBean(String beanName) throws BeansException {
		  DefaultListableBeanFactory acf = (DefaultListableBeanFactory) applicationContext.getAutowireCapableBeanFactory();
		  acf.removeBeanDefinition(beanName);
	  }

	  /**
	  * 获取对象
	  * @param name
	  * @return Object 一个以所给名字注册的bean的实例
	  * @throws BeansException
	  */
	  public static Object getBean(String name) throws BeansException {
	    return applicationContext.getBean(name);
	  }

	  /**
	  * 获取类型为requiredType的对象
	  * 如果bean不能被类型转换，相应的异常将会被抛出（BeanNotOfRequiredTypeException）
	  * @param name       bean注册名
	  * @param requiredType 返回对象类型
	  * @return Object 返回requiredType类型对象
	  * @throws BeansException
	  */
	  public static <T> T getBean(String name, Class<T> requiredType) throws BeansException {
	    return applicationContext.getBean(name, requiredType);
	  }

	  /**
	  * 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
	  * @param name
	  * @return boolean
	  */
	  public static boolean containsBean(String name) {
	    return applicationContext.containsBean(name);
	  }

	  /**
	  * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
	  * 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
	  * @param name
	  * @return boolean
	  * @throws NoSuchBeanDefinitionException
	  */
	  public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
	    return applicationContext.isSingleton(name);
	  }

	  /**
	  * @param name
	  * @return Class 注册对象的类型
	  * @throws NoSuchBeanDefinitionException
	  */
	  public static Class<?> getType(String name) throws NoSuchBeanDefinitionException {
	    return applicationContext.getType(name);
	  }

	  /**
	  * 如果给定的bean名字在bean定义中有别名，则返回这些别名
	  * @param name
	  * @return
	  * @throws NoSuchBeanDefinitionException
	  */
	  public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
	    return applicationContext.getAliases(name);
	  }

	/**
	 * 如果给定类型，返回所有的bean
	 * @param requiredType
	 * @return
	 * @throws NoSuchBeanDefinitionException
	 */
	public static <T> Map<String,T> getBeans(Class<T> requiredType) throws NoSuchBeanDefinitionException {
		return applicationContext.getBeansOfType(requiredType);
	}
}
